1. Field of the Invention
The present invention relates to a sealing method of a liquid crystal display panel and a sealing apparatus for a liquid crystal display panel, particularly to a sealing method and a sealing apparatus appropriate for sealing a filling port regarding a small size liquid crystal display panel with the liquid crystal has been filled.
2. Description of the Related Art
In a conventional sealing method of a liquid crystal display panel 1, as shown in FIG. 1, a pair of substrates 2 opposing to each other are first joined by a sealing agent with a predetermined distance. Next, the liquid crystal is filled from a filling port 4 into a gap 3. Then, the filling port 4 is sealed by an ultraviolet ray curing sealing agent (an adhesive agent) 6. And then, a mask 8 where an opening that matches to the filling port 4 is formed covers the ultraviolet ray curing sealing agent 6, an ultraviolet ray 9 is irradiated in this state to cure the ultraviolet ray curing sealing agent 6 only at the filling port 4, and thus a cured area 6a is obtained. In a region where the ultraviolet ray 9 is blocked by the mask 8, the ultraviolet ray curing sealing agent 6 is an uncured area 6b. Thereafter, the uncured area 6b is removed by an organic solvent. Such a method is described in Japanese Patent No. 2882376.
Alternatively, a method has been developed in which a plurality of the liquid crystal display panels 1 are adhered and arranged in a block state and the ultraviolet ray curing sealing agent is coated on the block body utilizing a dispenser having a coating orifice of a long hole state.
These sealing methods are appropriate for sealing the hole of the liquid crystal display panel 1 of a current normal size. However, coating of ultraviolet ray curing sealing agent and curing processing by the ultraviolet ray irradiation are not feasible regarding a smaller size liquid crystal display panel, and a quality reduces.
Specifically, in a sealing process in the small size liquid crystal display panel, the number of the panel in a batch treatment is more than that of the current size liquid crystal display panel. For example, although 40 to 80 pieces are processed as one batch in the current size, 280 to 480 pieces are processed as one batch in the small size. Since processing time per one batch is longer accordingly, the time difference of the coating of the ultraviolet ray curing sealing agent at the first and the last part of the processing is larger than that of the current case of the liquid crystal display panel. As a result, this threatens to reduce a quality and a yield.
This is because the time difference of the processing for the liquid crystal display panel in the initial coating period and the liquid crystal display panel in the last coating period becomes large when the ultraviolet ray curing sealing agent is coated on the filling port by the dispenser method of the prior art, and the time difference threatens to occur mixing and the like of the ultraviolet ray curing sealing agent into a display plane of the liquid crystal display panel in which the liquid crystal is filled. As described, in the liquid crystal display panels processed in one batch, prevention of the ultraviolet ray curing sealing agent into the display plane is difficult and a quality reduction may occur, and thus improvement of the yield may be difficult. Accordingly, in a sealing technology of the small size liquid crystal display panel, the technology development that reduces the coating time difference of the ultraviolet ray curing sealing agent is desired.
Further, when coating of the ultraviolet ray curing sealing agent is executed utilizing the conventional dispenser, the ultraviolet ray curing sealing agent drops on the display plane of the liquid crystal display panel. Accordingly, the quality threatens to reduce and the yield may not improve. This is because management of a coating shape and a coating amount is difficult when the filling port is sealed by using the conventional dispenser. In other words, this is because the ultraviolet ray curing sealing agent may protrude from an end surface of the filling port to adhere to the display plane.
When the ultraviolet ray curing sealing agent adheres to the display plane, there are problems such that a polarizing plate cannot be adhered, and the panel cannot be directly used as the liquid crystal display panel. Thus, an operation is required such that an unnecessary portion is scraped off. At this point, the liquid crystal display panel may be scratched, which causes a defective. Therefore, the development of the technology is desired in which the coating shape and the coating amount of the ultraviolet ray curing sealing agent can be easily managed in coating the ultraviolet ray curing sealing agent.
The object of the present invention is to provide a sealing method of a liquid crystal display panel and a sealing apparatus for a liquid crystal display panel that reduce the coating time difference of the ultraviolet ray curing sealing agent and that can easily manage the coating shape and the coating amount of the ultraviolet ray curing sealing agent particularly when the filling port of the small size liquid crystal display panel is sealed.
According to one aspect of the present invention, a sealing method of a liquid crystal display panel comprises the steps of: arranging a plurality of liquid crystal display panels having filling ports to fill liquid crystal; transferring an ultraviolet ray curing sealing agent in a wet state to each of the filling ports by a transfer roller in a lump; and irradiating an ultraviolet ray to the ultraviolet ray curing sealing agent.
According to another aspect of the present invention, a sealing apparatus for a liquid crystal display panel comprises a cassette in which a plurality of liquid crystal display panels having filling ports to fill liquid crystal; and a transfer roller which transfers a ultraviolet ray curing sealing agent in a wet state to each of the filling ports in a lump.
According to the present inventions, when the liquid crystal is filled in the liquid crystal display panel and the hole is sealed, the liquid crystal is filled in the gap between a pair of substrates of the liquid crystal display panel from the filling port. And, a plurality of the liquid crystal display panels are arranged. And then, the ultraviolet ray curing sealing agent in a wet state is transferred on each filling port by a transfer roller in a lump. Thereafter, the ultraviolet ray is irradiated to cure the agent, and the filling ports are closed and sealed.
According to the present invention, complicateness of a manufacturing process is solved in comparison with the sealing of the filling port by the conventional dispenser method, the sealing process of the filling port is performed faster as a processing, and thus the small size liquid crystal display panel can be commercialized more inexpensively. In addition, a product with high reliability and high quality can be obtained because of good yield.
If opposing substrates of the liquid crystal display panel are pressed with each other by a pressurizing unit, for example, the gap of the liquid crystal display panel is controlled, and the positional accuracy and the coating amount of the ultraviolet ray curing sealing agent coated on the small size liquid crystal display panel can be stabilized.
If residual liquid crystal of the liquid crystal display panel is wiped in a lump by a wiping unit, for example, the positional accuracy and the coating amount of the ultraviolet ray curing sealing agent coated on the small size liquid crystal display panel can be stabilized.
If an ultraviolet ray to the ultraviolet ray curing sealing agent through a mask with an opening which matches to the filling port by a ultraviolet ray irradiation device, for example, only the ultraviolet ray curing sealing agent coated on the filling port can be cured, the accuracy of an irradiation position and the irradiation amount of the ultraviolet ray to the small size liquid crystal display panel can be stabilized.
If a coating state of the ultraviolet ray curing sealing agent to the filling ports and an sealing state by the ultraviolet ray irradiation are confirmed with a sensor, for example, the positional accuracy and the coating amount of the ultraviolet ray curing sealing agent coated on the small size liquid crystal display panel can be stabilized by recognizing a coated state in an image processing to detect the defective.